This application claims priority of Application No. H09-339648, filed Dec. 10, 1997 in Japan, the subject matter of which is incorporated herein by reference.
The present invention relates to a method and an apparatus for fabricating a semiconductor device. More particularly, the present invention is directed to a method and an apparatus for fabricating a semiconductor device, in which a semiconductor wafer is delivered by a conveyer to a wafer treatment device and is thermally treated.
In a process for fabricating a semiconductor device, a semiconductor wafer is thermally treated. For example, in a diffusion process, an electrode formed on a compound semiconductor wafer is sintered.
A conventional sinter furnace includes a heating chamber, in which a semiconductor wafer is heated, and a cooling chamber, in which the semiconductor wafer is cooled down. In such a conventional sinter furnace, a semiconductor wafer is conveyed by a delivery arm, between a loader cassette and the heating chamber; between the heating chamber and the cooling chamber; and between the cooling chamber and an un-loader cassette.
Semiconductor wafers contained in the loader cassette are controlled in temperature at about 20xc2x0 C. The heating chamber includes a hot plate controlled in temperature at 450xc2x0 C. The cooling chamber includes a cooling plate controlled in temperature at 20xc2x0 C.
According to the conventional apparatus, a semiconductor wafer of the room temperature is rapidly heated up when the wafer is put onto the heating plate in the heating chamber. The temperature of the semiconductor wafer changes too rapidly, and therefore, the semiconductor wafer may be broken by heat-shock phenomenon. In addition, a semiconductor wafer, which has been heated in the heating chamber, is rapidly cooled down when the wafer is taken out from the heating chamber. That is because the delivery arm is at the room temperature of about 20xc2x0 C., which is 430xc2x0 C. different from the semiconductor wafer, which has been already heated. As a result, the semiconductor wafer may be broken by cool-shock phenomenon. Once a semiconductor wafer is broken, semiconductor devices formed thereon can not be used anymore. The above-described problems are remarkable and more serious to compound type of semiconductor wafers, such as GaAs wafers.
Accordingly, an object of the present invention is to provide a method for fabricating a semiconductor device in which a semiconductor wafer is prevented from being broken, caused by rapid temperature variation.
Another object of the present invention is to provide an apparatus for fabricating a semiconductor device in which a semiconductor wafer is prevented from being broken, caused by rapid temperature variation.
Additional objects, advantages and novel features of the present invention will be set forth in part in the description that follows, and in part will become apparent to those skilled in the art upon examination of the following or may be learned by practice of the invention. The objects and advantages of the invention may be realized and attained by means of the instrumentalities and combinations particularly pointed out in the appended claims.
According to a first aspect of the present invention, a method for fabricating a semiconductor device includes the steps of: thermally treating a semiconductor wafer with a wafer treatment device; delivering the semiconductor wafer by conveyer to the wafer treatment device; and controlling the temperature of the conveyer to have an optimum temperature.
According to a second aspect of the present invention, an apparatus for fabricating a semiconductor device, includes a wafer treatment device which applies a thermal treatment to a semiconductor wafer; a conveyer which delivers the semiconductor wafer to and from the wafer treatment device; and a controller which controls the temperature of the conveyer to have an optimum temperature.
As described above, according to the present invention, the conveyer is controlled in temperature, therefore, it can be avoided that the temperature of the semiconductor wafer is changed too rapidly. As a result, the semiconductor wafer is prevented from being broken due to heat-shock (rapid heating) or cool-shock (rapid cooling).